Substituting Soda Ash for Lye?

Hello, bakers! Anybody out there use soda ash, also known as sodium carbonate or washing soda, to boil your bagels in? I saw the discussion about using lye found in the plumbing section of the hardware store; that just won't pass the wife test around here. But soda ash is sold as a pool chemical called "pH Up", and since it goes in water that, presumably, won't kill you if you drink it by accident, wouldn't that imply that it is safer for food use?